Zanubrutinib

Evidence Level: L5

Predicted Indications: 6

Zanubrutinib

Pharmacist Assessment Report

Zanubrutinib: From Mantle Cell Lymphoma and B-Cell Malignancies to Myeloid Leukaemia

One-Sentence Summary

Zanubrutinib is an oral Bruton tyrosine kinase (BTK) inhibitor, originally used for mantle cell lymphoma and other B-cell malignancies. The TxGNN model predicts it may be effective for myeloid leukaemia, but there is 1 clinical trial (a Phase 1 study with weak relevance) and no publications that directly study zanubrutinib in this disease.

Quick Overview

Item	Content
Original Indication	Mantle cell lymphoma, B-cell neoplasm, lymphosarcoma (the ARTG record compiled for this report carries no indication text)
Predicted New Indication	Myeloid leukaemia
TxGNN Prediction Score	0.9965
Evidence Level	L5 (mechanistic rationale only; no direct clinical studies in myeloid leukaemia)
Australia Market Status	Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data
Number of PBS Items	1 (valid: 1)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. Zanubrutinib is a selective, covalent BTK inhibitor. BTK is a core part of B-cell receptor signalling, and this is why the drug works in B-cell cancers such as mantle cell lymphoma, chronic lymphocytic leukaemia (CLL) and Waldenström macroglobulinaemia.

BTK is also expressed in myeloid-lineage cells, where it contributes to B-cell receptor, Toll-like receptor and chemokine signalling. This gives a biological rationale for the model’s prediction.

However, the link is indirect. The publications retrieved concern zanubrutinib in CLL/SLL, mantle cell lymphoma and Waldenström macroglobulinaemia, not myeloid leukaemia. The only trial found tests a different drug (PRT2527, a CDK9 inhibitor), with zanubrutinib as one possible combination partner in a B-cell malignancy setting. The high TxGNN score is not backed by direct clinical evidence.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrolment	Key Findings
NCT05665530	Phase 1	Completed	86	Dose-escalation study of PRT2527 (CDK9 inhibitor) alone or combined with zanubrutinib or venetoclax in relapsed/refractory haematologic malignancies. Results are not summarised in the data compiled. Relevance to myeloid leukaemia is weak.

Literature Evidence

None of the publications below studies zanubrutinib in myeloid leukaemia. They cover related B-cell diseases and general safety.

PMID	Year	Type	Journal	Key Findings
39647999	2025	RCT (Phase 3)	J Clin Oncol	SEQUOIA 5-year follow-up: zanubrutinib vs bendamustine plus rituximab in treatment-naive CLL/SLL
36400069	2023	Cohort (Phase 2)	Lancet Haematol	Zanubrutinib in B-cell malignancies intolerant of earlier BTK inhibitors
40334067	2025	Cohort	Blood Adv	Updated results: zanubrutinib well tolerated and effective in CLL/SLL patients intolerant of ibrutinib/acalabrutinib
40829104	2026	Cohort	Blood Adv	Pooled analysis of zanubrutinib in CLL/SLL with del(17p) and/or TP53 mutation (N = 301)
34959482	2021	Review	Pharmaceutics	Tyrosine kinase inhibitors in chronic leukaemias (CML and CLL)
36402930	2023	Review	Leukemia	BTK inhibitors in Waldenström macroglobulinaemia
37150651	2023	Cohort	Clin Lymphoma Myeloma Leuk	Hepatitis B reactivation in patients receiving BTK inhibitors, including zanubrutinib
42192981	2026	Review	Cancers	BTK inhibitors in CLL: selectivity, hypogammaglobulinaemia and infection risk
36325357	2022	Case report	Front Immunol	Rare coexistence of Waldenström macroglobulinaemia and B-cell ALL; not efficacy evidence

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
12891L	Brukinsa	Capsule 80 mg (oral)	Not stated in the record compiled for this report

Cytotoxicity

Item	Content
Cytotoxicity Classification	Targeted therapy (BTK inhibitor), not a conventional cytotoxic
Myelosuppression Risk	Please refer to the Product Information (PI) warnings and precautions. Cytopenias are a recognised concern with this drug class.
Emetogenicity Classification	Please refer to the PI. This is an oral targeted agent.
Monitoring Items	Full blood count (with differential) is the main parameter. Also consider liver function and hepatitis B status, given reports of HBV reactivation with BTK inhibitors.
Handling Protection	Please refer to the PI and local institutional policy for oral anticancer agents

Safety Considerations

Drug Interactions: The interaction screen returned 100 interacting drugs. The Major-level interactions in the portion reviewed include:
- Aprepitant
- Acetylsalicylic acid (aspirin)
- Dexamethasone
- Clarithromycin
- Cobicistat
- Deferasirox
- Deferiprone
- Samarium (153Sm) lexidronam
- Ibritumomab tiuxetan
- Tositumomab (I-131)
Moderate-level interactions include cimetidine, miconazole, clotrimazole and several others.
Literature-based concerns: The retrieved publications report hepatitis B virus reactivation with BTK inhibitors, and hypogammaglobulinaemia with increased infection risk.

Warnings and contraindications from the TGA-approved Product Information were not available. Please refer to the PI for full safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: The TxGNN score is high, but no direct evidence supports zanubrutinib in myeloid leukaemia. The only trial is an early-phase study of a different drug, and the literature covers B-cell diseases. The rationale for BTK signalling in myeloid cells has not been tested clinically.

To proceed, the following is needed:

Preclinical or translational data showing BTK dependence in myeloid leukaemia models
Detailed mechanism of action data
Results and cohort details from NCT05665530, to see whether any myeloid patients were treated with zanubrutinib
TGA-approved PI warnings and contraindications, to complete safety screening
Consideration of other predicted indications for this drug. B-cell non-Hodgkin lymphoma (rank 9) has far stronger trial and publication support, though it largely extends the existing B-cell neoplasm label.
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.